1. Field of the Invention
The field of the present invention is shaped-articles made of fibers for use in producing fiber-reinforced composite members, and methods for producing the same.
2. Description of the Prior Art
There are conventionally known fiber shaped-articles of such a type formed of short fibers such as whiskers. In general, such a shaped-article is formed by a producing process comprising the steps of pouring into a forming mold a slurry-like forming material comprising short fibers dispersed in liquid, removing the liquid and, at the same time, accumulating the short fibers.
In the conventional shaped-article, however, the short fibers have a specific orientation with their lengthwise direction being substantially perpendicular to an accumulating direction. For this reason, in a fiber-reinforced composite member made therefrom, an anisotropy is provided in characteristics thereof, resulting in a problem that such a fiber-reinforced composite member is unsuitable for application to a structural member to which a multi-axial stress is applied, such as a functional member including slide portions slidable in different directions and the like. In addition, the conventional fiber shaped-article tends to be of a small thickness and to increase in density, due to the producing process therefor, resulting in a problem that it is impossible to meet the needs for increasing the thickness and reducing the density.
The conventional producing process also is accompanied by a problem that the accumulated mass is liable to increase in density, as the liquid is removed. For this reason, gaps for drainage between the short fibers in the accumulated mass are reduced, thereby requiring a lot of time for removing the liquid, resulting in an inferior productivity of the fiber shaped-article.
A hybrid type shaped-article is employed in order to provide the fiber-reinforced composite member with various characteristics, for example, both strength and wear resistance. In this instance, the reinforcing fibers may be different in specific gravity in many cases due to the difference between their compositions. If the conventional producing process is utilized in order to produce a fiber shaped-article of such a type, reinforcing fibers having a high specific gravity are sedimented faster than reinforcing fibers having a low specific gravity, resulting in a hybrid type shaped-article comprised essentially of two layers: a portion formed of the reinforcing fibers of high specific gravity and a portion formed of the reinforcing fibers of low specific gravity, and, therefore, it is impossible to produce a hybrid type shaped-article with reinforcing fibers of a high specific gravity being dispersed uniformly therein.